Faculty Bibliography

BACKGROUND AND OBJECTIVES/OBJECTIVE:Trans-sonolucent cranioplasty ultrasonography (TCUS) has been explored as a noninvasive tool for evaluating superficial temporal artery (STA)-middle cerebral artery (MCA) bypass patency. Previous research has focused on early postoperative feasibility. Data on its long-term utility and correlation with formal angiography remain scarce. We aimed to evaluate TCUS' role in postoperative STA-MCA bypass graft monitoring and its concordance with formal angiography. METHODS:This retrospective study included 46 consecutive direct STA-MCA anastomoses in 40 patients (March 2021-May 2024), all with sonolucent polymethyl methacrylate cranioplasty. Patient records were reviewed for demographics, disease and surgical characteristics, and outcomes. Postoperative TCUS was performed outpatient to monitor anastomotic patency. Formal follow-up angiography was also conducted, and radiographic data were reviewed for graft patency assessment and qualitative correlation with TCUS. RESULTS:Follow-up angiography was performed for 41 of 46 anastomoses (digital subtraction angiography, n = 34; computed tomography angiography, n = 4; magnetic resonance angiography, n = 3) at a median of 1.1 years, demonstrating 97.6% patency (40/41). Outpatient TCUS was performed in 32 of 46 bypasses (69.6%) with 100% patency at first scan (median 28.5 days). A second TCUS (n = 19, 41.3%) at a median of 8.4 months (3.9-13.6 months) showed robust flow in 94.7% of cases. One bypass had asymptomatic slow flow with a narrowed anastomosis, and another showed a severely stenosed STA correlating with later digital subtraction angiography. In the broader cohort, third (n = 5, median 1.2 years) and fourth (n = 1, 1.4 years) TCUS assessments demonstrated 100% patency. Among bypasses undergoing both TCUS and angiography (n = 31, 67.4%), findings were concordant in all cases. CONCLUSION/CONCLUSIONS:TCUS demonstrated complete agreement with formal angiography in assessing bypass patency, supporting TCUS as a reliable, noninvasive monitoring tool. Future research should explore quantitative TCUS flow measurements and their relationship to intraoperative flow and long-term graft remodeling.

Background Arteriovenous malformations (AVMs) in eloquent brain regions pose significant challenges due to the increased risk of neurologic deficits associated with treatment. Although stereotactic radiosurgery (SRS) and endovascular embolization are used as standalone approaches, their comparative outcomes in eloquent brain AVMs remain unclear. Purpose To directly compare the outcomes of standalone endovascular embolization versus SRS for patients with AVMs in the eloquent brain. Materials and Methods This retrospective multicenter study analyzed patients with AVMs located in eloquent brain regions treated with standalone SRS or embolization from January 2010 to December 2023 as part of the Multicenter International Study for Treatment of Brain AVMs, or MISTA, consortium. Angiographic outcomes were assessed using digital subtraction arterial angiography, MR angiography, or CT angiography. Propensity score weighting (PSW) was used to account for baseline differences. Results A total of 119 patients were included (median age, 35 years [IQR, 21-54 years]; 64 female), with 96 patients treated with SRS and 23 with embolization. SRS achieved 71% (61 of 86 patients) complete obliteration at last follow-up compared with 56% (10 of 18 patients) in the embolization group (odds ratio [OR], 1.95; P = .20) before adjustment. After PSW, SRS achieved higher odds of complete obliteration at last follow-up (OR, 15.58; P = .001) compared with embolization. Before PSW, the SRS group had higher rates of modified Rankin Scale (mRS) scores 0-2 at last follow-up (95% [86 of 91 patients] vs 71% [15 of 21 patients]; OR, 6.8; P = .004) and a lower rate of hemorrhagic complications (5.2% [five of 96 patients] vs 26% [six of 23 patients]; OR, 0.15; P = .005) compared with embolization. Mortality rates were 2.1% (two of 96) in the SRS group and 4.3% (one of 23) in the embolization group (OR, 0.46; P = .54). After PSW, there was no evidence of a difference between SRS and embolization in mRS scores 0-2 (OR, 2.04; P = .45) or hemorrhagic complications (OR, 0.60; P = .63). Conclusion SRS was associated with a higher obliteration rate compared with embolization in patients with eloquent brain AVMs, whereas there was no evidence of a difference in functional outcomes or complications after adjustment. © RSNA, 2025 See also the editorial by Russell in this issue.

BACKGROUNDAND OBJECTIVE/UNASSIGNED:The authors compareocclusion rates in grade I-III AVMs in smokers and non-smokers, using propensity score matching (PSM). METHODS:The authors performed a subgroup analysis of the MISTA consortium, a multicenter registry that includes patients aged 1 to 89 years with AVMs treated between January 2010 and December 2023. Only grade I-III AVMs were included. PSM was used to control confounders. Primary endpoints included angiographic obliteration. RESULTS:A total of 353 patients with bAVMs, with a median age of 37, were included in this study: 236 were never smokers, and 117 were current or previous smokers. After 1:1 PSM of smokers and non-smokers, 33 matched pairs were obtained. The smokers were more likely to display complete obliteration at last imaging follow-up compared to non-smokers (57.6 % vs. 27.3 %;p < 0.01). The median time to last clinical(p = 0.45)and angiographic(p = 0.33)follow up was not statistically different between the two groups.There were no statistically significant differences between the two matched groups in the incidence of post-SRS edema (p = 0.23), post-treatment rupture (0 %), overall mortality (p = 0.31), and functional status at the last follow-up (p = 0.69). CONCLUSION/CONCLUSIONS:Individuals with a positive history of smoking are more likely to achieve complete obliteration of grades I-III bAVMs following SRS treatment. However, smokers do not differ from non-smokers in terms of the incidence of post-treatment rupture, overall mortality, or functional status at the last follow-up.

BACKGROUND AND IMPORTANCE/BACKGROUND:Marfan syndrome's association with intracranial aneurysms, though controversial, poses unique challenges for surgical intervention because of the inherent vascular fragility. Open surgical approaches carry considerable risk. Endovascular flow diversion with the Pipeline embolization device (PED) offers a less invasive alternative, and adjunctive coiling can decrease occlusion time for complex aneurysms. We report the first combined use of PED and coiling to treat a Marfan-associated intracranial aneurysm, detailing our operative approach and reviewing the literature. CLINICAL PRESENTATION/METHODS:mutation was incidentally found to have an unruptured paraophthalmic aneurysm during stroke workup. Diagnostic angiography revealed an irregular superior hypophyseal aneurysm along with tortuous and irregular internal carotid arteries suggesting previous dissections. The aneurysm was successfully treated with a PED and adjunctive coil embolization. The patient was discharged on aspirin and clopidogrel. Six-month follow-up angiography confirmed aneurysm occlusion. Although there was no residual or recurrent aneurysm at 2-year follow-up, imaging revealed 2 de novo intracranial aneurysms. The patient remains asymptomatic and under observation. CONCLUSION/CONCLUSIONS:mutations and cerebrovascular pathology.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Arteriovenous malformations (AVMs) with perinidal aneurysms and single draining vein are associated with an elevated risk of rupture and increased procedural complexity. The role of preoperative embolization in this high-risk anatomical subset remains unclear. This study aimed to evaluate the safety and efficacy of microsurgery with preoperative embolization, compared with microsurgery alone in patients with such AVMs. METHODS:We conducted a multicenter retrospective analysis of an AVM registry from the MISTA (Multicenter International Study for Treatment of Brain AVMs) consortium and included AVMs with perinidal aneurysms and a single draining vein. Baseline characteristics, angiographic outcomes, functional outcomes, and complication rates were compared. Propensity score weighting (PSW) using the covariate balancing method was applied to adjust for baseline differences. RESULTS:Out of a total of 1919 patients, 65 met the inclusion criteria; 45 patients underwent preoperative embolization followed by microsurgery, and 20 underwent microsurgery alone. After adjustment, complete obliteration rates were similar between groups (OR 0.87, 95% CI 0.04 to 16.33, P=0.92), as were rates of functional independence at discharge and follow-up. Overall complication, symptomatic complication, and mortality rates did not differ significantly between groups. However, permanent complications were significantly lower in patients with preoperative embolization (OR 0.06, 95% CI 0.004 to 0.84, P=0.03). DISCUSSION/CONCLUSIONS:In patients with AVMs featuring perinidal aneurysms and single draining vein, preoperative embolization followed by microsurgery was associated with fewer permanent complications and no increase in adverse outcomes compared with microsurgery alone. However, given the small number of events, this finding should be interpreted cautiously.

BACKGROUND:Osteogenesis imperfecta (OI) is a connective tissue disorder characterized by fragile bones and vascular fragility, increasing the risk of vessel dissection and potentially complicating endovascular intervention. The authors present the first case of cranial bypass in a patient with OI. OBSERVATIONS/METHODS:A 38-year-old male with OI type I presented with a symptomatic left internal carotid artery (ICA) occlusive dissection managed with endovascular revascularization and stenting. Follow-up surveillance imaging identified an incidental right ICA dissection, also treated with stenting. Four years later, the patient experienced new right hemispheric symptoms. He was found to have progressive right ICA dissection on best medical management. Following an unsuccessful restenting attempt, he underwent a successful double-barrel superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass to restore cerebral perfusion with no perioperative complications. Six-month follow-up DSA confirmed a patent bypass with robust flow, and the patient remained asymptomatic 1 year postoperatively. LESSONS/CONCLUSIONS:STA-MCA bypass can serve as a viable and effective revascularization option in patients with OI, whose disease predisposes them to vascular dissection. In these high-risk patients, cranial bypass is a safe method for effective flow augmentation to hypoperfused brain regions when endovascular interventions fail. https://thejns.org/doi/10.3171/CASE25378.

Definitive endoluminal reconstruction, widely known as flow diversion, revolutionized treatment of brain aneurysms. A range of targets, by location, size, etiology, and acuity, can be cured with an excellent risk/benefit profile. Requirement for effective antiplatelet state is balanced with superior treatment durability. Implant and delivery system technology continue to evolve. Some aneurysm types/locations remain undertreated. Maximizing efficacy while minimizing risks requires deep understanding of flow diversion principles, pathologic anatomy, endoluminal implants, delivery systems, and clinical management.

BACKGROUND:Brain arteriovenous malformations (AVMs) are abnormal connections between feeding arteries and draining veins, associated with significant risks of haemorrhage, seizures and other neurological deficits. Preoperative embolization is commonly used as an adjunct to microsurgical resection, with the aim of reducing intraoperative complications and improving outcomes. However, the efficacy and safety of this approach remain controversial. METHODS:This study is a subanalysis of the Multicenter International Study for Treatment of Brain AVMs consortium. We retrospectively analysed 486 patients with brain AVMs treated with microsurgical resection between January 2010 and December 2023. Patients were divided into two groups: those who underwent microsurgery alone (n=245) and those who received preoperative embolization, followed by microsurgery (n=241). Propensity score matching was employed, resulting in 288 matched patients (144 in each group). The primary outcomes were rates of complete AVM obliteration and functional outcomes (measured by the modified Rankin Scale (mRS)). Secondary outcomes included complication rates, mortality, hospital length of stay and postsurgical rupture. RESULTS:After matching, the complete obliteration rate was 97% with no significant difference between the microsurgery-only group and the preoperative embolization group (p=0.12). The proportion of patients with an mRS score of 0-2 at the last follow-up was similar in both groups (83% vs 84%; p=0.67). The median hospital stay was significantly longer for the embolisation group (9 days vs 7 days; p=0.017). Complication rates (24% vs 22%; p=0.57) and mortality rates (4.9% vs 2.1%; p=0.20) were comparable between the two groups. No significant differences were observed in postsurgical rupture, recurrence or retreatment rates. CONCLUSIONS:In this large multicentre study, preoperative embolization did not significantly improve AVM obliteration rates, functional outcomes or reduce complications compared with microsurgery alone.

The anatomy of vertebrobasilar perforators has been widely studied in human cadavers, with most reports found in the neurosurgical literature. These arterial perforators are extremely hard to visualize consistently with traditional two-dimensional digital subtraction angiography, but are reliably visible with cross sectional cone beam CT techniques. A clear understanding of this specific neurovascular anatomy and pathology is essential for informed treatment decisions. This review analyzes the anatomy of vertebrobasilar perforators with a focus on practical implications for aneurysm treatment, particularly flow diversion.

BACKGROUND:With transradial access (TRA) being more progressively used in neuroendovascular procedures, we compared TRA with transfemoral access (TFA) in middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH). METHODS:Consecutive patients undergoing MMAE for cSDH at 14 North American centers (2018-23) were included. TRA and TFA groups were compared using propensity score matching (PSM) controlling for: age, sex, concurrent surgery, previous surgery, hematoma thickness and side, midline shift, and pretreatment antithrombotics. The primary outcome was access site and overall complications, and procedure duration; secondary endpoints were surgical rescue, radiographic improvement, and technical success and length of stay. RESULTS:872 patients (median age 73 years, 72.9% men) underwent 1070 MMAE procedures (54% TFA vs 46% TRA). Access site hematoma occurred in three TFA cases (0.5%; none required operative intervention) versus 0% in TRA (P=0.23), and radial-to-femoral conversion occurred in 1% of TRA cases. TRA was more used in right sided cSDH (58.4% vs 44.8%; P<0.001). Particle embolics were significantly higher in TFA while Onyx was higher in TRA (P<0.001). Following PSM, 150 matched pairs were generated. Particles were more utilized in the TFA group (53% vs 29.7%) and Onyx was more utilized in the TRA group (56.1% vs 31.5%) (P=0.001). Procedural duration was longer in the TRA group (median 68.5 min (IQR 43.1-95) vs 59 (42-84); P=0.038), and radiographic success was higher in the TFA group (87.3% vs 77.4%; P=0.036). No differences were noted in surgical rescue (8.4% vs 10.1%, P=0.35) or technical failures (2.4% vs 2%; P=0.67) between TFA and TRA. Sensitivity analysis in the standalone MMAE retained all associations but differences in procedural duration. CONCLUSIONS:In this study, TRA offered comparable outcomes to TFA in MMAE for cSDH in terms of access related and overall complications, technical feasibility, and functional outcomes. Procedural duration was slightly longer in the TRA group, and radiographic success was higher in the TFA group, with no differences in surgical rescue rates.